A unique 10-digit identifier for every tax lot in NYC, composed of borough code, block number, and lot number.
Last updated: March 2026 · 9.4M+ properties indexed
BBL stands for Borough-Block-Lot and is the primary identifier for real property in NYC. The format is:
Example: 1-00835-0001 = Manhattan, Block 835, Lot 1 (the Empire State Building)
BBL is more reliable than street addresses for property research because addresses can be ambiguous (corner lots, buildings with multiple entrances), while BBL is unique and unambiguous.
You can find a property's BBL on tax bills, through DOF's property lookup, or by searching any address on RegWatch.
BBL stands for Borough-Block-Lot — the unique 10-digit identifier assigned to every tax lot in NYC.
Check the property tax bill, search on DOF's website, or enter the address into RegWatch.
Addresses can be ambiguous (corner lots, multiple entrances), while BBL is unique and unambiguous for every tax lot.
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